Grids

The DESK downloads and fits both new and commonly-used model grids, automatically. The grids are also available for download on Zenodo. Columns are in wavelength (um) and flux density (W*m-2).

DUSTY model grids

The DUSTY models are 1-D radiative transfer models that exploit scaling relations to generate models. The model shape can be scaled to any luminosity, expansion velocity, or mass-loss rate so long as the combination of these three parameters remains the same. The DESK model grids contain 2,000–32,000 unique model shapes. Theses grids are scaled to the desired number of luminosities between 1,000 and 150,000 solar luminosities using the command option –n.

> desk fit --source='example.csv' --grid='corundum-mix' --n=10

This command will scale the ‘corundum-mix’ model grid of 3,000 unique model shapes to luminosities at 1000, 17555, 34111, 50666, 67222, 83777, 100333, 116888, 133444, and 150000 solar luminosities (30,000 models).

The output model parameters of expansion velocity and gas mass-loss rate are scaled using the relations from Elitzur & Ivezić 2001. The model flux is scaled using the brightness and distance to the sun, and scaling for the luminosity which is already in solar luminosities.

Only the default carbon (amorphous-carbon) and oxygen-rich (silicates) model grids are downloaded during installation. Additional grids are downloaded when selected. The number of unique models and the file size of each grid are specified next to the grid names below.

Except where stated otherwise, the models assume a standard MRN grain size distribution from 0.005 - 0.25 microns. The DUSTY code uses an analytical approximation of the wind density distribution. This calculation extends to a distance of 10,000 times the inner radius (density type = 4, within the DUSTY code).

Oxygen-rich DUSTY model grids

comarcs-oxygen-atmosphere (N=5; 0.1 MB): The grid is based on oxygen-rich atmospheric COMARCS models with effective temperature (2600-3400 K: 100 K interval). This model grid assumes no dust.

silicates (N=2,000; 3.4 MB): Uses oxygen-rich warm silicates from Ossenkopf et al. (1992) and a black body. This grid provides ranges in effective temperature (2600-3400 K: 200 K interval) inner dust temperature (600-1200K: 200 K interval) and optical depth (0.1 - 30: 100 spaced logarithmically).

o-def-silicates (N=2,000; 3.4 MB): Same as the silicates grid but using oxygen-deficient warm silicates from Ossenkopf et al. (1992).

corundum-mix (N=3,000; 5 MB): Same temperature range as the silicates grid but with with more limited density of optical depths (0.1 - 30: 50 spaced logarithmically) created for three scenarios of different fractions of warm silicates and corundum grains from Begemann et al. (1997). The fractions included are 70:30, 80:20, 90:10 for the warm silicates:corundum grain ratio.

crystalline-mix (N=3,000; 5 MB): Same as corundum-mix but with crystalline silicate grains from from Jaeger et al. (1994).

draine-mix (N=3,000; 5 MB): Same as corundum-mix but with astronomical silicate grains from from Draine & Lee (1984).

iron-mix (N=2,960; 5 MB): Same as corundum-mix but with iron grains from Henning et al. (1995),.

carbon-mix (N=3,000; 5 MB): Same as corundum-mix but with amorphous carbon grains from Zubko et al. (1996).

silicate-mix (N=71,435; 127 MB): This grid provides ranges in effective temperature (2600-3400 K: 200 K interval) inner dust temperature (600-1200K: 100 K interval) and optical depth (0.1 - 30: 100 spaced linearally). We set 4% iron grains from Henning et al. (1995), and different fractions of the oxygen-rich and oxygen-deficient grains from Ossenkopf et al. (1992) and crystalline silicates from Jaeger et al. (1994). The fractions for each grain type are 0, 16, 24, 38, 42, 56, 64, 80% for the oxygen-rich and oxygen-deficient silicates with the remainder filled with the crystalline silicates and 4% iron grains.

Explore this model grid using the interactive notebook

galactic-bulge-OH-IR (N=7,500; 124 MB): The oxygen-rich grid used in for Goldman et al. (2025) The grid is based on atmospheric COMARCS models with effective temperature (2600-3400 K: 200 K interval) inner dust temperature (600-1200K: 100 K interval) and optical depth (0.1 - 30: 100 spaced linearally) and optical depth (0.1 - 50: 50 spaced linearally). The models use a grain composition of 4% metalic iron (Ordal et al. 1988) and fractions of armorphous and crystalline silicates. The crystalline fraction is set to 1, 3, 6, 10, or 15%, with the remaining fraction filled with amorphous silicates. These models are the full hydrodynamical solution for the density structure of the wind.

galactic-bulge-OH-IR-mmrn (N=7,500; 124 MB): Same as galactic-bulge-OH-IR but with a MRN grain size distribution with a larger maximum allowable grain size of 0.5 micron.

Carbon-rich DUSTY model grids

comarcs-carbon-atmosphere (N=7; 0.1 MB): The grid is based on carbon-rich atmospheric COMARCS models with effective temperature (2400-3400 K: 100 K interval). This model grid assumes no dust.

amorphous-carbon (N=1,340; 145 MB): Same as silicates but with amorphous carbon grains from Zubko et al. (1996).

Dust growth grids

The dust growth model grids from Nanni et al. (2019).

H11-LMC (N=90,899; 770 MB): A carbon-rich grid for the LMC metallicity (1/2 solar) using optical constants from Hanner et al. (1988).

H11-SMC (N=91,058; 772 MB): A carbon-rich grid for the SMC metallicity (1/5 solar) using optical constants from Hanner et al. (1988).

J1000-LMC (N=85,392; 723 MB): A carbon-rich grid for the LMC metallicity (1/2 solar) using optical constants from Jaeger et al. (1998)

J1000-SMC (N=85,546; 724 MB): A carbon-rich grid for the SMC metallicity (1/5 solar) using optical constants from Jaeger et al. (1998)

2-D model grids

The GRAMS model grids

The GRAMS model grids from Sargent et al. (2011) and Srinivasan et al. (2011). These models assume a density distribution of 1/r², a modified KMH dust grain distribution, and an assumed expansion velocity of 10 km/s. Compared to the 1D DUSTY models, the optical depths for the GRAMS models are more limited, with optical depths at 10 microns ranging from 0.001-0.4 for the carbon-rich grid, to 0.0001-26 for the oxygen-rich grid.

grams-carbon (N=12,244; 41.3 MB): A 2D carbon-rich grid using the 2DUST code for the LMC metallicity (1/2 solar) using optical constants from Zubko et al. (1996).

grams-oxygen (N=68,601; 200 MB): A 2D oxygen-rich grid using the 2DUST code for the LMC metallicity (1/2 solar) using optical constants from Ossenkopf et al. (1992).

grams: Both GRAMS datasets combined

- Warning: results uncertain outside of a distance 20-150 kpc.